 
(* ::Section:: *)
(* Polarization *)
(* ::Text:: *)
(*Polarization[k] is the head of a polarization momentum with (incoming) momentum k. A slashed polarization vector (e1(k) slash) has to be entered as GS[Polarization[k]]. The internal representation for a polarization vector e1 corresponding to a boson with four momentum k is: Momentum[ Polarization[ k, I ] ]. With this notation transversality of polarization vectors is provided, i.e. , Pair[ Momentum[k], Momentum[ Polarization[k, I] ] ] yields 0. Polarization[k,-I] denotes the complex conjugate polarization. Polarization is also an option of various functions related to the operator product expansion. The setting 0 denotes the unpolarized and 1 the polarized case..*)


(* ::Subsection:: *)
(* See also *)
(* ::Text:: *)
(*PolarizationVector, PolarizationSum, DoPolarizationSums.*)



(* ::Subsection:: *)
(* Examples *)



Polarization[k]

Polarization[k]//StandardForm

Polarization[k]//ComplexConjugate

Polarization[k]//ComplexConjugate//StandardForm

GS[Polarization[k]]

GS[Polarization[k]]//StandardForm

Pair[ Momentum[k], Momentum[ Polarization[k, I] ] ]
